The present invention generally relates to reverse osmosis filtration purification systems including a plurality of filter cartridges connected together in series for selectively and sequentially removing specific kinds of impurities from a tap water supply. More particularly, it relates to a fluid flow control apparatus which mountingly receives each of the filter cartridges to be used and directs fluid flow internally between the filters within the filter section and connects the filter section to other elements of the overall R.O. purification system.
Reverse osmosis filtration purification systems are increasingly being employed to purify municipal and well water supplies to provide improved drinking water for the home, for use in ice makers, vending machines, humidifiers, for watering indoor plants and the like. Many applications require that more than one filter be employed in series to selectively remove different impurities. Frequently, a series of filters is needed due to the fact that some R.O. membrane filters and other speciality filters are sensitive to or do not work well if the incoming water contains for example, chlorine. In these situations chlorine is first removed from the feed water in a pre-filter before it is fed into the chlorine-sensitive filter positioned downstream.
Various filter cartridges have been developed for use in these systems. Examples include sediment filters, granular activated carbon (GAC) filters, reverse osmosis membrane filters including thin film, cellulose, cellulose acetate, cellulose triacetate and hollow-fiber types, specialty filters for removing lead, iron, nitrates, as well as, microfilters and ultrafilters. Filter cartridges containing both mechanical and chemical removal media generally have a standardized cylindrical configuration including entry and outlet structures for attaching the filters to other system elements.
The filter cartridges are placed in standardized pressure vessels and incoming feed water passes into the vessel and through the filter under pressure. Flow through the filter module including the filter cartridge and pressure vessel may vary depending on the type of filter cartridge employed. Some filters work by directing incoming fluid along the periphery of the filter and vessel. Water is forced through the removal media to enter a centrally disposed tube or passage defined in the filter. Product water within the central tube may flow concurrently or counter currently with respect to the feed water flow entering the vessel. R.O. filters typically have three ports to the module including an impure water inlet, a product water outlet and a concentrate or waste water outlet.
Different combinations of these filters in series will require different specific fluid flow connections between the filters, due to variations in flow requirements for each filter in the series. Conventionally, the various flow connections within the filter section from one filter to another and between the filter section and the remainder of the R.O. system are made using polytubing provided with coupling adaptors. A major disadvantage associated with these polytube linked networks is leakage. The systems operate under pressure and each and every coupling provides a potential site for leakage.
Another disadvantage of these systems is that changeover of filters within the system is burdensome. Some tubing connections must be detached before a pressure vessel can be removed from the filter series and the filter cartridge replaced. Every time the tubing sections are disconnected and reconnected, the risk of leakage in the system increases. Moreover, some systems present such a complicated network of criss-crossing tubes, that a skilled technician is needed to make repair calls.
In order to overcome the disadvantages of the prior art systems, it is an object of the present invention to provide a filter section fluid flow control apparatus which significantly reduces or eliminates the need for polytubing connections between filter modules.
It is another object of the invention to provide a self-contained filter section having a simple connectorized input/output connection to other system elements.
It is a further object of this invention to provide a substantially tubeless fluid flow control device for a filter section including quick disconnect features for the filter modules to facilitate changeover and repair.
It is still another object of the present invention to provide a new and improved filter section for use in R.O. systems having a pop-in pop-out feature enabling the entire filter section to be disconnected and removed as a unit from the remainder of the system for repair or substitution by a new filter section unit which may contain the same or different filter cartridges.